Ow been approved for treating wrinkles, skin discoloration, and blemishes due to photoaging. At high doses, however, it can cause very severe irritation. generic viagra Redness and peeling may be reduced by administering tretinoin first to get the skin acclimated. More research is needed to determine whether tazarotene produces any long-lasting significant benefits. Warning: pregnant women and those who may become pregnant should avoid any vitamin a derivative (a product related to vitamin a). Oral tretinoin causes birth defects. Vitamin c. Vitamin c, or ascorbic acid, is a very potent antioxidant. Most studies on the effects of antioxidants on the skin have used this vitamin. In laboratory studies, large amounts of vitamin c reduced skin swelling and protected immune factors from sunlight. Vitamin c may even promote collagen production. Vitamin c by itself is unstable, but products that solve the delivery problem are now available (such as cellex-c, avon's anew formula c treatment capsules, physician elite, and others). One study found that a combination of topical vitamin c and madecassoside (which stimulates collagen production) significantly improved wrinkles, skin firmness, roughness, and hydration. Antioxidants under investigation for skin care. Other antioxidants are also being investigated for their value in skin protection. Most available brands, however, contain very low concentrations of these antioxidants. In addition, the antioxidants are not well absorbed and have only a short-term effect. New delivery techniques, however, may offset some of these problems. Vitamin e. Studies suggest that topical vitamin e, particularly alpha tocopherol cream (a form of vitamin e), decreases skin roughness, length of facial.